Ion-exchange Fibers Research Articles

Fibrous anion exchanger with ternary amino groups as a component of the substrate for plants growing

A set of studies necessary to determine the suitability of a fibrous anion exchanger with ternary amino groups based on industrial polyacrylonitrile fiber Nitron C as a component of ion substrates was carried out. A laboratory-prepared ion exchanger sample had a working exchange capacity equal to 0.9 meq/g for the nitrate anion, which limits the biological productivity of the substrate for growing plants, in the physiological pH range = 5.5–7.5 and the concentration of the equilibrium nutrient solution is 0.02 eq/l. This capacity is at the level of the best granular ion exchangers and significantly exceeds the capacity of the previously used fibrous ion exchangers for growing plants in zero gravity conditions on space stations in 1970–1994 (Mir, Soyuz TM-10 – TM-17). The synthesized ion exchanger is a polyampholyte and contains three types of ion exchange groups, has high hydrophilicity and mechanical properties that allow it to be processed into textiles and used for any purpose, in which fibrous ion exchangers can be used (air and water purification, human protection means, etc.).

Silver nanoparticles in electrospun ethyl hydroxy ethyl cellulose-PVA Nanofiber: Synthesis, characterization and wound dressing applications

Electrospinning is a simple, cost-effective technique and a reproducible process for both synthetic and natural polymers. It is found to be an attractive tool for various applications in biomedical engineering, filtration, protective clothing, catalysis reactions and sensors. Non-ionic cellulose ethers namely Ethyl Hydroxy Ethyl Cellulose (EHEC) is an important polysaccharide which is non-toxic, biocompatible and biodegradable and finds applications as thickening/rheology control agents in paints, cosmetics, detergents, oil recovery and also in the biomedical area. Poly (vinyl alcohol) (PVA) is a semi-crystalline hydrophilic polymer which is highly biocompatible and non-toxic having good thermal and mechanical properties and also high water solubility. Silver shows powerful antimicrobial activity and is non-toxic. It has been used to cure severe burns and chronic ulcers for many decades and is extensively used as an additive in various fields like prostheses, burn treatment, catheters, vascular grafts, dental resin components, ion exchange fibers, stainless steel materials, human skin and coating of medical devices. In the present work, EHEC/PVA nanofibers embedded with silver nanoparticles (AgNPs) are studied for their antibacterial activity using both gram positive and gram negative bacteria. The nanofibers show increase in tensile properties with the addition of silver nano-particles. The AgNPs embedded EHEC/PVA nanofiber mats having 0.5% AgNPs were found to enhance the wound healing with no scar formation in wistar rats. The biological in-vitro and in-vivo studies support the potential of EHEC based nanofibers as excellent bio-materials for the treatment of severe burns and wounds. To the best of our knowledge, this is the first report on the electrospinning of EHEC/PVA nanofibers for wound healing applications.

Application of ion-exchange fibers towards the chromatographic separation of valuable metals of Ni, Co, Ce, La and Nd from spent nickel-metal hydride batteries

Recycling valuable metals from spent nickel-metal hydride (NiMH) batteries has significant environmental and economic benefits. This study aimed to separate and recover nickel (Ni), cobalt (Co), cerium (Ce), lanthanum (La), and neodymium (Nd) from waste NiMH batteries using ion-exchange fibers as the adsorbent material in an adsorption chromatography process. Static adsorption experiments showed the metal adsorption processes followed the Langmuir model, indicating mono layer coverage, and quasi-second order kinetics, suggesting chemisorption. In the chromatographic separation study, optimal conditions of pH 2, 1/10 diluted feed solution, fully packed column, 3 mL/min flow rate, and 0.2 mol/L acid elution enabled effective separation of the five metals. According to distribution coefficients, the metals were preferentially adsorbed in the order: Nd3+ > La3+ > Ce3+ > Co2+ > Ni2+. Transition metals Ni2+ and Co2+ were first separated from rare earths Ce3+, La3+ and Nd3+. Subsequently, good separation among the rare earth elements was achieved. After ten adsorption-desorption cycles, the fibers maintained excellent stability with only 9.2 % capacity loss. The results demonstrate the adsorption chromatography method can efficiently recover mixed metals from waste NiMH batteries individually for full value utilization.

Facile and cost-effective fabrication of activated charcoal-carboxymethyl cellulose composite fiber for high-rate water-softening application

Sustainable cost-effective activated charcoal-carboxymethyl cellulose (AC-CMC) fiber was developed through a benign method for high-rate water-softening applications. The as-developed fiber was characterized using FTIR, BET, stereomicroscope, XRD, and FESEM. The fiber was not only used for the removal of hardness (adsorptions of Ca(II) and Mg(II)) from different aqueous media but also successfully applied in a membrane system. The effect of pH, contact time, isotherm, and kinetic experiments were conducted to examine the sorption efficiency of the fiber. The fiber showed an adsorption efficacy of 46.1 mg/g and fast rate kinetics of 0.1521 L/min for Ca(II). The results were compared to that of the commercial ion-exchange fibers and beads namely Fiban K-1 and 001X8 NA, respectively. The experimental results fitted the best with the Langmuir isotherm and pseudo-first-order kinetic models. It can be assumed that the electrostatic and dipole-ion interactions between the fibers and Ca(II)/Mg(II) played a vital role during the sorption process. The fiber also showed proficient reusability performance. The developed fiber was applied in the membrane system and it showed high breakthrough bed volume within a short residence time of 25.7 seconds. So, this work demonstrates the significant potential of the AC-CMC fiber for high-rate water-softening application in the membrane system.

Sorption of ammonium by fibrous sorbent VION KN-1

The results of studies of the sorption extraction of ammonium ions from aqueous media by the fibrous sorbent VION KN-1 are presented. Weak acid ion exchange fiber. It has been established that the limiting step in the process of ammonium ion sorption is internal diffusion. The kinetic parameters of the sorption process are calculated, with the identification of a decrease in the half-sorption time and an increase in the internal diffusion coefficient. The applicability of the Langmuir and Freindlich models for describing the experimental isotherms of ammonium ion sorption by fiber has been studied. Certain constants and parameters. Through the appearance of regression coefficients, R2 showed that the Langmuir model better explores experimental data on the sorption of ammonium ions by a fibrous sorbent. A study of sorption in media was carried out. According to the curves of the dependence of the degree of extraction on the concentration and on the depth of the missed solution, it was found that with a decrease in concentration in the dynamic sorption mechanism, the reduction characteristics do not decrease, which makes their use reduced in the purification of dilute solutions containing ammonium ions. At a low concentration of ammonium ions in the initial solution, the degree of extraction is more than 93%. To predict the extraction of ammonium ions from wastewater, an increased concentration of neural packages of STATISTICA application programs was used. The input parameters for studying the neural network were chosen: the concentration of ammonium ions, the volume of the solution passed through the sorbent layer, and the weight of the sample of fibers. The output parameter is the degree of extraction of ammonium ions. The trained MPL-3-5-1 neural network has high coefficients of determination for the training, test and control samples, which gives a high estimate of the network performance and can predict the degree of extraction of ammonium ions by the fibrous sorbent VION KN-1..

High-capacity/high-rate hybrid column for high-performance ion exchange

Herein, a fixed-bed high-capacity/high-rate (HC/HR) hybrid column was developed using commercial ion-exchange beads (IEBs) and ion-exchange fibers (IEFs). The as-fabricated HC/HR hybrid column exhibited excellent breakthrough bed volume (BV) and utilization efficiency of capacity (UEC) at a high service flow rate (SFR) for the adsorption of Cd(II). The IEBs displayed a high adsorption capacity of 235.2 ± 9.8 mg g−1 and slow adsorption kinetics (k2 = 0.0001 g mg−1 min−1) for the sorption of Cd(II); meanwhile, the IEFs showed a maximum adsorption capacity of only 146.3 ± 7.5 mg g−1, which is lower than that of the IEBs, but fast kinetics (k2 = 0.0130 g mg−1 min−1). At an SFR of 104.23 BV h−1, the HC/HR hybrid column showed excellent performance for the sorption of Cd(II), having a high breakthrough BV of 1009.11 and a UEC of 92.86%; these values are much higher than those of the IEB-packed column. Furthermore, at an increased SFR (318.47 BV h−1), the HC/HR hybrid column maintained its high performance, demonstrating a breakthrough BV of 568.80 and UEC of 83.90%. The regeneration experiment indicates that 97% of the initial capacity was retained. Thus, the HC/HR hybrid column could easily be applied to existing column systems and shows promising performance in ion-exchange processes.

High Efficiency Uranium(VI) Removal from Wastewater by Strong Alkaline Ion Exchange Fiber: Effect and Characteristic.

In this study, we analyzed the removal efficiency of uranium(U(VI)) in wastewater at relatively low concentrations using strong alkaline ion exchange fiber (SAIEF). Static tests showed that the strong alkali fibers can purify U(VI) containing wastewater in a concentration range of 20-100 mg L-1 with an optimal pH of 10.5 and contact time of 15-30 min. Adsorption and desorption cycling tests indicated that, adsorbed uranium is easily desorbed by 0.1 mol L-1 HCl, and the fiber still maintained the original adsorption efficiency after eight cycles. According to dynamic penetration test results, the SAIEF saturation adsorption capacity was 423.9 mg g-1, and the effluent concentration of uranium through two series columns was less than 0.05 mg L-1, reaching the national standard for non-receiving water (GB23727-2009) SEM-EDS and FTIR analysis revealed that the functional group of SAIEF is CH2N+(CH3)3Cl-. Addotionally, the major forms of fiber exchange adsorption are (UO2)2CO3(OH)3-, UO2(CO)34- and UO2(OH)3-. The results indicate that the SAIEF is an excellent material for uranium removal.

ИНЖЕНЕРНОЕ ОБЕСПЕЧЕНИЕ ПРИМЕНЕНИЯ ИОНООБМЕННЫХ ВОЛОКОН В «МОКРЫХ» ТЕХНОЛОГИЯХ. МЕМБРАННАЯ ФИЛЬТРАЦИЯ

An experimental verification of the expediency of using membrane technologies as one of the options for engineering support of the use of ion-exchange fibers for solving environmental problems is discussed. Comparative data on the sorption of cations by the protonated and sodium forms of the ion-exchange fiber are presented. It is shown that membrane filtration is a rather effective means of providing optimal operating conditions for radial filtration cartridges made of ion-exchange fibers.

Esterification of stearic acid using novel protonated and crosslinked amidoximated polyacrylonitrile ion exchange fibres

This study will demonstrate the conversion of stearic acid to methyl stearate (biodiesel) using for the first time crosslinked amidoximated polyacrylonitrile ion-exchanged mesh protonated by sulphuric acid. Quantitative analysis of conversion was by GC-FID, 1H NMR and ATR-FT-IR with GC-FID the most reliable. A molar ratio of methanol to stearic acid of 35.5: 1 gave 94 % conversion to the ester at 90 °C. At 65 °C and a greater ratio of 87.1:1 conversion was 94.1 % comparable to the 98 % yield obtained with 1wt% H2SO4. Re-use at 65 °C gently dropped to 57 % on the 13th cycle. Regeneration by washing with dichloromethane and re-acidification achieved 84 % conversion but quickly deactivated due to blocking of sites by methyl stearate as shown by ATR-FTIR. This protonated amidoxime PAN catalyst (distinct from sulfonated fibres) exhibited higher stability than other heterogeneous protonated catalysts (ion-exchange resins, zeolites, clays) used lower temperatures and shorter reaction times. Advantages of using a mesh in place of powders are its ease of removal/replacement for continuous flow reactors promoting quick changes in process parameters. This study is promising as providing a sustainable protonated catalyst for use in converting Fats, Oils and Greases (FOG’s) in waste oils and wastewater to biodiesel.

Removal of metal ions from cyanide gold extraction wastewater by alkaline ion-exchange fibers

The metal cyanide complex ions of gold extraction wastewater consume extra cyanide and compete with gold for adsorption on activated carbon during wastewater recycling. Therefore, the removal of metal cyanide complex ions from gold extraction wastewater is of great significance. In this study, polypropylene (PP) fibers were used to prepare strong acylated alkaline ion-exchange fibers (SAA-IEFs) using a polymer graft monomer method that achieved excellent adsorption of metal cyanide complex ions from gold extraction wastewater. The properties of the SAA-IEFs were characterized via scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Fourier transform infrared (FT-IR) spectroscopy, and thermogravimetric analysis (TGA). Adsorption experiments were conducted to study the adsorption performance and to verify the adsorption mechanism. The results show that the highest adsorption efficiencies of the SAA-IEFs for zinc and copper cyanide complex ions were 85.5% and 91.2%, respectively, and these performances were obtained when the SAA-IEF concentration was 50 g/L and pH was 10. The adsorption efficiency of the cyanide complexes in practical wastewater reached 92% at a concentration of 30 g/L. The desorption and regeneration results indicate that the adsorption capacity of the SAA-IEFs remained high after nine cycles. Moreover, an adsorption mechanism is proposed, and the adsorption process is best modeled using the Freundlich isotherm and pseudo-second-order kinetic model. These results indicate that chemisorption plays a dominant role in the adsorption process. Overall, SAA-IEFs are a promising, efficient, and cost-effective adsorbent for metal cyanide complex ion adsorption from gold extraction wastewater.

Imparting ion-exchange properties to fibrous polycaproamide materials by chemically initiated graft copolymerization

The study of the types and properties of surgical threads, as well as the experience in the production of suture surgical material and its use shows that the most promising for surgical practice are threads with antimicrobial properties. Of the methods for fixing medicinal compounds with chemical bonds for suture materials, the most expedient is their attachment by the reaction of ion-exchange interaction. Since polycaproamide (PCA) practically does not contain functional groups, a preliminary modification stage is required to impart ion-exchange properties to PCA fibrous materials. One of these stages of modification is the process of graft polymerization of methacrylic acid (MAA) in order to create active groups on the fiber, for example, peroxide or hydroperoxide. Modification of chemical fibers by graft copolymerization with inogenic monomers is one of the widespread methods of obtaining fibrous ion exchangers. Principles, new approaches and technologies for imparting ion-exchange properties to fibrous polycaproamide materials by chemically initiated graft copolymerization have been developed. Regularities in the production of fibrous PCA of sorption active materials by chemical initiation by a redox system (Fe2++H2O2) located in a modifying bath, as well as by pre-oxidation of fiber PCA in order to create peroxide and hydroperoxide groups on the fiber, are revealed.

Anion- and cation-exchange studies of Zr, Hf, and Th using ion-exchange resin and fiber in H2SO4 media for chemical characterization of sulfate complex of Rf

Anion- and cation-exchange studies of Zr, Hf, and Th using ion-exchange resin and fiber in H2SO4 media for chemical characterization of sulfate complex of Rf

Separation and Recovery Process of Copper (II) and Nickel (II) from Wastewater Using Ion Exchange Fiber

AbstractIn this paper, the parameters affecting the adsorption of CuII and NiII by PAN‐NHx fiber and PAN‐COONa fiber were discussed firstly, such as initial ion concentration, pH, and temperature. Secondly, influence factors toward the separation of CuII and NiII by PAN‐NHx fiber were systematically evaluated by single‐column experiments. The results showed that the PAN‐NHx fiber had good separation of CuII and NiII; NiII accounts for more than 99.00 % of total metal ion content in the initial 1000 mL effluent, while CuII is less than 1 %. With the changed from CCuII: CNiII=90 %:10 % to 95 %:5 %, the ratio of CCuII: CNiII in the treated effluent changed from 6 %: 94 % to 2 %: 98 % (fed flow rate: 0.42 BV min−1). The adsorption capacity of PAN‐NHx adsorption column was well maintained after six cycles. Finally, based on the above laboratory results, a multi‐column process was designed to separate and recover CuII and NiII from wastewater.

Titration of weak base fibrous anion exchangers in the presence of complex-forming divalent cations

Curves of potentiometric titration of fully protonized fibrous ion exchangers with potassium hydroxide against the background of 1 M KCl in the presence of chlorides of Ni2+, Со2+, Сu2+ and Ca2+ were obtained. The ion exchangers were synthesized by modifying of industrial polyacrylonitrile fiber with diethylenetriamine and triethylenetetraamine and predominantly contained functional groups R-CO-NH- (CH2CH2NH)nH (n = 2 or 3) and a small amount of carboxyl groups. The sorption of Ni2+, Со2+, Сu2+ и Ca2+by ion exchangers was calculated from the data obtained depending on the pH of the medium. It was found that the investigated ion exchangers with high selectivity sorb heavy metal ions in a wide range of acidity of solutions (pH 2–9) due to the formation of metal-polymer complexes with polyamine functional groups. The maximum sorption capacity is 1.5–2.7 and 4–5 meq/g for ion exchangers with n = 2 and 3, respectively.

WATER ROLE IN THE GASES CHEMOSORPORATION PROCESSES BY SORPTION-ACTIVE MATERIALS

The work summarizes the literature data on the hydration and chemisorption of toxic gases by polymeric sorption-active materials. The mechanisms of absorption by granular and fibrous ion-exchange and impregnated materials and the state of adsorbed water have been studied using various research methods (gravimetric, sorption-thermochemical, derivatographic, IR spectroscopic). The regularities of the hydration processes of granular strongly acidic sulfonic cationexchangers of the brands KU‑2 and KU‑23 (macroporous analogue), fibrous strongly acidic sulfonic cation- exchanger VION KS‑3, fibrous weakly acid carboxylic cation exchanger VION KN‑1 in various ionic forms are considered. Among the anion exchangers, the hydration of granular strongly basic anion- exchangers of the brand AV‑17, granular weakly basic anionexchangers of the brands AN‑25 (AN‑251 macroporous analogue) and ANKB‑35, fibrous strongly basic anion- exchangers of the brands FIBAN A‑6 and FIBAN A‑12, fibrous medium basic anion- exchangers of the brands CM‑2, fibrous weakly basic anion- exchangers of the brands CM-A1, VION AN‑1, VION AN‑3, FIBAN A‑5, FIBAN A‑11 and FIBAN AK‑22 are considered. It has been established that, by nature, the bond with the active centers of water is derided into a «bound» and a ordiner – «free». The first one is a monolayer and the nearest bonded with the ion of the ball; the other is the osmotic swelling water. It has been shown that for the effective absorption of most toxic gases and vapors (SO2, HCl, Cl2, SiF4, HF, NO2, NH3, аміни, COCl2, O3), it is necessary to have «free» water, which is not only a diffusion medium in which mass transfer proceeds, but also is a direct participant in chemisorption.

ADSORBATIVE SEPARATION OF DOXYCYCLINE FROM AQUEOUS SOLUTION WITH N,N-DIETHYL N-METHYL CHITOSAN, GUM AND POLYACRYLIC ACID BASED HYDROGELS

The separation and purification of antibiotics with sorption by ion-exchange materials, as well as their delivery in biological processes by immobilization, are now widely used in biotechnology. There are many scientific studies in the literature on the sorption of antibiotics by polymer-based sorbents and inorganic materials, as well as the study of thermodynamics and kinetics of the process. In the literature, the acquisition of biologically active systems from the sorption of antibiotics by ion-exchange fibers based on various polymers and inorganic substances was carried out. However, the synthesis of selective gels for the effective separation of doxycycline and its delivery in different pH mediums by sorption with biodegradable, biocompatible polysaccharide-containing composites is one of the topical issues. Gel was synthesized from the cross-linking of N,N-diethyl N-methyl derivative of a natural polyaminosaccharide of chitosan by glutaric aldehyde. Also, pH-sensitive hydrogels that can swollen in water were synthesized from the cross-linking of a graft copolymer of cherry source gummiarabic with N-vinylpyrrolidone, as well as synthetic polymer polyacrylic acid with N,N-methylene-bis-acrylamide. The structure of the gels were identified by FTIR and NMR spectroscopy, and the sorption of doxycycline antibiotic from an aqueous solution was investigated. According to the values of zeta potential, the protonation of functional groups in the main macromolecule in an acidic medium leads to a value of zeta potential of 40÷80 mV on the surface of chitosan-based gel and others. Although the chemical structure is different, the isoelectric point is set around pH=6÷8 for all three hydrogels. The dependences of the sorption process on the amount of gels, antibiotic concentration, temperature, and pH medium were studied. The experimental data were analyzed using two adsorption models, Langmuir and Freundlich, with the later system providing the best fit. Doxycycline is adsorbed on the surface of chitosan, gummiarabic and polyacrylic acid based hydrogel composite through by physical interactions. Also, the results of thermodynamic parameters ΔG40 kJ/mol show that the nature of the adsorption process is physical, and spontaneous, too. Keywords: Chitosan, Gummiarabic-arabinogalactane, polyacrylic acid, hydrogel, sorption isoterms, doxycycline, thermodynamica.

Dynamic Sorption of Carbonate Forms of Uranium(VI) with FIBAN Fibrous Ion Exchangers

Dynamic Sorption of Carbonate Forms of Uranium(VI) with FIBAN Fibrous Ion Exchangers

Interaction of Bacterial Collagenase with the Matrix of Chitosan Ion-Exchange Fibers, Chitosan, and Chitosan Succinate During Immobilization

Interaction of Bacterial Collagenase with the Matrix of Chitosan Ion-Exchange Fibers, Chitosan, and Chitosan Succinate During Immobilization

Equilibrium of ion exchange of calcium, magnesium and potassium for proton on fibrous carboxylic ion exchanger

By the method of potentiometric titration of a fibrous aminocarboxylic polyampholyte with a predominant content of carboxyl groups, the equilibrium of the cation exchange of calcium, magnesium, and potassium ions for a hydrogen ion was studied. Due to the low solubility of calcium and magnesium hydroxides in these cases, titration was carried out by Ca(OH)2 and Mg(OH)2, which are formed in solution upon contact with the H-form of the ion exchanger оf increasing portions of solid CaO and MgO. This made it possible to obtain titration curves in a wide range of pH and calcium and magnesium chlorides concentration (0–0.1 eq./L). The dependences of the swelling of ion exchangers on the neutralization degree with the bases of the studied cations are obtained. The coefficients of ion-exchange equilibria are calculated. It was found that the swelling of the ion exchanger is relatively little dependent on its ionic form. The ion exchanger has a higher affinity for calcium than magnesium ion.

Studies of the Processes of the Trypsin Interactions with Ion Exchange Fibers and Chitosan

Studies of the Processes of the Trypsin Interactions with Ion Exchange Fibers and Chitosan